The present invention relates to an altitude compensating wastegate control system for a turbocharger which automatically compensates for decreased air density and barometric pressure at high altitudes by bleeding off, in preselected steps, the pressure in an air line supplying intake manifold pressure to an actuator of the turbocharger wastegate, thereby raising the intake manifold pressure level required before the wastegate of the turbocharger opens. The preselected steps are selected by the control system in response to sensed barometric pressure to produce different bleed configurations without requiring a dedicated feedback circuit.